Embossing of polymeric materials has been previously proposed to change the properties of the material. For example, in U.S. Pat. No. 6,394,651 and U.S. Pat. No. 6,394,652 it is proposed to provide embossed patterns in the material of flexible polymeric bags to enable the bags to stretch and better accommodate the bag contents. Each embossed pattern is in the form of parallel embossed ribs and is spaced from adjacent embossed patterns by unembossed regions. The arrangement permits stretch of the bag material in a selected direction.
An embossed film is also described in U.S. Pat. No. 6,472,084. In this disclosure the film is an elastic film suitable for use as a waistband and comprises a highly elastic core layer with polyolefin embossed surface layers. The embossing includes uniform unidirectional parallel marks in the machine direction. The film has activation zones and non-activation zones which are described as having sufficient elasticity and non-elasticity, respectively, to stretch to at least 200% while maintaining a permanent set percent of no more than 5% and tear strengths as measured by the Elmendorf Tear Test of 30 g and 50 g, respectively. A film with such a high degree of stretch would not be suitable for use in a bag such as a garbage bag.
The embossed films in the described prior proposals are designed to stretch and, in the case of the multi-layered elastic film of U.S. Pat. No. 6,472,084, to be tear resistant. There remains a need for a flexible polymeric film suitable for use as a disposable bag and having improved tear resistance.
It has been discovered that embossing flexible polymeric film aids in the reduction of tears or punctures developing when selected patterns of embossing are employed.
Thus, it is one aim of the present invention to provide a flexible polymeric film having embossing which alleviates the formation of tears or punctures.